1. Field of the Invention
The present invention pertains to conveyors for transferring frozen confections from a conveyor on which such confections are frozen to a position where they can be wrapped or otherwise processed, and more particularly, it pertains to such conveyors which rely upon scissorlike gripping tongs to grasp the confection during the transfer movement.
2. Description of the Prior Art
In the U.S. Pat. No. 3,985,223 to Forcella et al, there is disclosed an apparatus for producing frozen confections without molds in continuously moving processing lines. Such apparatus includes a freezer conveyor which includes a series of plates mounted to an endless chain. The freezer conveyor is arranged under an extrusion nozzle and slicing apparatus which together form a semi-frozen product, such as a slab of ice cream mix. The conveyor then carries the slab into a freezing vault through a spiralled series of runs within the vault until the products are frozen to a very hard consistency. The frozen products are then carried from the vault to the pickup zone of a pickup conveyor. The pickup conveyor includes a large number of carriages mounted in an endless series to form an endless chain. Each carriage includes a pair of tongs and means for scissoring the tongs so as to sequentially and continuously pick up frozen products from the plates of the outlet reach of the freezer conveyor. The frozen products are carried by the respective carriages through various optional accessory devices along the path of the pickup conveyor, such as through an enrober or coating bath for coating the frozen product with liquid chocolate and such as a dry-coating apparatus for subsequently covering the chocolate coated product with ground nuts. As shown in the Forcella et al patent, the overall frozen confection apparatus may further include a stick inserter for making stick-type confections and an extruder which is particularly adapted to make ice cream cones. Another typical confection machine of the same general type as that shown in the Forcella et al patent is that disclosed in U.S. Pat. No. 3,648,625 to Glass.
As noted in the Forcella at al patent, the moldless frozen confection apparatus must be adapted to produce different types of frozen confection products such as the ice cream slabs just described, rectangular frozen stick confections, ice cream sandwiches, ice cream cones, ice cream cups, and irregular novelty bars. Due to the wide range of sizes and configurations of such products, the Forcella et al patent noted that the pickup conveyor is required to include a large assortment of accessories, or changeover parts, to enable the conveyor assembly to handle the various frozen confections. Although the Forcella et al structure made a major contribution toward minimizing the inventory of parts required for the pickup conveyors and toward minimizing the length of time required to refit the pickup conveyor with different parts to handle different confections, the Forcella et al structure has been found to be subject to several shortcomings.
One shortcoming is that the carriages disclosed in the Forcella et al patent have to be individually and separately adjusted to set the distance between the gripping tongs when such tongs are closed upon the confection, such distance being hereinafter referred to as the "closed distance". That is to say, when a different type of confection that has a different width is to be handled by the product conveyor, each of the carriages must be individually adjusted to compensate for the new width of the confections to be picked up. It is noted that such adjustment of the Forcella et al carriages takes a considerable period of time, not only because each carriage has to be individually and directly manipulated but also because the adjustment of each carriage requires that a wrench be applied to a nut that is located at the inner end of the carriage. It will be appreciated by those in this art that these adjustments must accurately reset the closed distances, otherwise the tongs may tend to be either so far apart as not to pick up a product from the freezer conveyor or so closely spaced that the tongs become so deeply embedded in the frozen confection that they do not properly release the confection. In the latter case, when the tongs are opened at the drop station of the pickup conveyor, the confection may be stuck to one or both of the tongs so as to cause it to fall haphazardly onto the underlying takeaway conveyor or miss the conveyor altogether.
Another problem associated with the pickup conveyor in the aforedescribed prior art frozen confection handling systems is that such systems usually require a relatively expensive auxiliary conveyor disposed to receive certain types of confections at the drop station of the pickup conveyor. Such auxiliary conveyor is required except when ice cream cones are being handled. The auxiliary conveyor includes an endless series of contoured, stainless steel buckets which serve to orient the rectangular confections thereof before the confections are subsequently fed to the wrapper conveyor.
A typical wrapper conveyor of the prior systems is shown in the aforementioned Forcella et al patent. It includes an endless belt moving between transversely spaced, downwardly and inwardly sloped platforms; the endless belt has pusher lugs which are longitudinally spaced to receive confections between each adjacent pair of lugs. The auxiliary conveyor was required because the prior are pickup conveyors had carriages and means for opening the tongs of the carriages wherein the tongs could not be so rapidly opened that the product would be released quickly enough to fall in predictable uniform trajectories onto the underlying conveyor. In particular, the carriages of the Forcella et al type of pickup conveyor have been found to be incapable of so quickly releasing the confections that the confections drop in uniform trajectories at the drop zone of the pickup conveyor, thereby requiring the auxiliary transfer conveyor to compensate for irregular delivery before the confections are directed to the wrapping machinery.
Another problem associated with the pickup conveyor disclosed in the Forcella et al patent concerns the proper vertical positioning of the carriages relative to the freezer conveyor plates. In the Forcella et al structure, the pickup conveyor includes a frame that is vertically adjustable by means of several jacks, a chain for operating the jacks, and a crank for driving the chain. When it is desired to switch from a type of confection requiring one set of tongs to a confection requiring another set of tongs, in addition to making the aforementioned adjustment in the closed distances of the tongs, it is further necessary to manipulate the crank to adjust the height of entire pickup conveyor frame relative to the freezer conveyor so that the tongs of the carriages come into the desired registry with the sides of the new type of confections to be handled. Although such jack and crank arrangement of the Forcella et al system has been found to be generally satisfactory, it will be recognized that such arrangement is relatively costly and complex.
Yet another problem associated with this prior art pickup conveyor has to do with the infrequent, but very troublesome, problem of confections sticking to the plates of the freezer conveyor. As indicated in the Forcella et al patent, the freezer conveyor is provided with vibrating means below the outlet reach (upstream from the pickup zone of the pickup conveyor) to beat the undersides of the plates to loosen any confection which had become stuck to a freezer plate. It will be understood that such vibrating must be limited so that the confections are not shifted on the plates. Occasionally, such beating did not loosen all of the frozen confections from adherence to the plates. In such an event the stuck confection sometimes so tenaciously adheres to the supporting plate that the tongs of the pickup carriage fail to lift the confection from the plate. In the worst case, the tongs have become so embedded in a frozen-hard confection that damage has occurred to the carriage as a result.